You may want to change the power management mode in the nvidia control panel under 3d settings, manage 3d, power management, switch to prefer maximum.

Scarlet-Tech
I have classifieds, and don't get these crashes usually. What drivers are you running? What are your full system specs?

Take note, I am on a mobile platform and can not see signatures, so if it is in there, I will see it in a little bit. :-)

I'm using the latest beta driver, on Windows 8.1 Pro 64 bits. My specs are:
 
i7 2600k
Asus P8Z77-M Pro
Corsair AX850
Corsair 350D
1TB Seagate 7200RPM
Samsung 840 EVO 250GB
2x4GB Corsair Vengeance 1600Mhz

Scarlet-Tech
were you having the problem with the Drivers Prior to this Beta set?

Yes, with the official WHQL and the BETA the problem is the same.
 
It doesn't happen all the time, I changed to prefer to maximum performance as Scarlet said and seems to be solved now, but the card is way hotter than normal in idle

Scarlet-Tech
What is way hotter?  Sorry to ask so many questions, just trying to see what you see without eyes :-)
 
Have you changed the thermal paste?  I changed the thermal paste prior to watercooling, and the mass of thermal material was kind of nasty, and changing the TIM reduced everything a Lot.  May be something to consider.  If is only a few screws (Not all of them) to remove the cooler and change the TIM.  

The idle temps, because now with maximum performance set, there is no 324Mhz clock, GPU stays at 1000Mhz+ constantly

That is kind of strange... I have always run mine on Max performance, with dual monitors, and all 3 of my cards downclock to 324...
 
Try removing Precision X, Select no when it asks if you want to save profiles, and while it is gone, reload the drivers.  Download HWMonitor or GPU-z, if you don't have them already, and check how it is running with that rather than with precision.
 
Here are 3 pictures:  
 
This is Idle, Max Performance was off as I just re-installed drivers while trouble shooting an issue.  Folding was paused.

 
Folding running and Max Performance enabled.  Didn't even give it a chance to boost, so it stopped at 1019mhz as soon as I took the snip for the picture.

 
This last picture is Folding Paused, nothing else changed.  You can see the Graph in PX at the bottom go back to Idle.  

 
I think you have something in the background running and drawing power on your Classy, and it doesn't like Alt+Tab, and also won't let you go to idle.
 
How many monitors are you running?  I am currently on a Dual setup, 1080p 60Hz using DVI to HMDI cables. (didn't know anything about DVI/HDMI/Display Port connectors when I purchased)

Folding is Distributed computing.  It uses the resources of the GPU like Mining, but it doesn't pay out, except for up to 4 EVGA Bucks a month for certain amount of points.  I was just using it as an example. 
 
So, now that your question is answered, Azzazel99, what is your setup?  Full system specs, and number of monitors?

Monitor Size and Hz don't effect the Graphics, but resolution will.  Have you checked your programs and GPU usage, to make sure nothing is running in the background?